Scale is central to understanding nanotechnologies. These technologies are usually described as the understanding and control of matter at the nanoscale, with one nanometer being 10^-9 meter. At this scale, some materials gain new properties that can be used in the creation of new products. These properties may contribute to economic growth and social welfare but, conversely, they may also create negative effects, such as new risks to human health and the environment. As an emerging field whose consequences are still uncertain, the meanings of nanotechnologies are hotly contested